Share This

University of California researchers found that the incidence rate for all causes of dementia in people age 90 and older is 18.2% annually and significantly increases with age in both men and women. This research, called "The 90+ Study," is one of only a few to examine dementia in this age group, and the first to have sufficient participation of centenarians.

Related Articles

Findings of the study appear in the February issue of Annals of Neurology.

Dementia (senility) is a progressive, degenerative disorder that affects memory, language, attention, emotions, and problem solving capabilities. A variety of diseases cause dementia including Alzheimer's disease, stroke, and other neurodegenerative disorders. According to a 2000 report from the World Health Organization (WHO), approximately 6%-10% of the population 65 years and older in North America have dementia, with Alzheimer's disease accounting for two-thirds of those cases.

For their population-based, longitudinal study of aging and dementia, Maria Corrada, Sc.D., and colleagues invited members who were originally part of The Leisure World Cohort Study and 90 years of age or older as of January 1, 2003. As of December 31, 2007 there were 950 participants in The 90+ Study and 539 who had completed a full evaluation that included neurological testing, functional ability assessments and a questionnaire covering demographics, past medical history, and medication use. Evaluations were repeated every 6-12 months with a final dementia questionnaire completed shortly after death.

Analysis was completed on 330 participants who were primarily women (69.7%) between the ages of 90 to 102, and who showed no signs of dementia at baseline. Researchers identified 140 new cases of dementia during follow-up with 60% of those cases attributed to Alzheimer's disease (AD), 22% vascular dementia, 9% mixed AD and vascular dementia and 9% with other or unknown cause.

Dr. Corrada explained, "Our findings show dementia incidence rates almost double every five years in those 90 and older." Researchers found the overall incidence rate based on 770 person-years of follow-up was 18.2% per year. Rates increased with age from 12.7% per year in the 90-94 age group, to 21.2% per year in the 95-99 age group, to 40.7% per year in the 100+ age group. Incidence rates were very similar for men and women. Previous results from The 90+ Study found higher estimates of dementia prevalence in women (45%) compared to men (28%), a result also seen in other similar studies.

Prior reports estimate there were 2 million Americans aged 90 and older in 2007 and the number is expected to reach 8.7 million by 2050, making the oldest-old the fastest growing segment of the U.S. population. "In contrast to other studies, we found that the incidence of dementia increases exponentially with age in both men and women past age 90," said Dr. Corrada. "Given the population projections for this age group along with our findings, dementia in the oldest-old threatens to become an epidemic with enormous public health impact."

Story Source:

The above story is based on materials provided by Wiley-Blackwell. Note: Materials may be edited for content and length.

Wiley-Blackwell. "Dementia in extreme elderly population expected to become epidemic." ScienceDaily. ScienceDaily, 24 February 2010. <www.sciencedaily.com/releases/2010/02/100224103353.htm>.

Wiley-Blackwell. (2010, February 24). Dementia in extreme elderly population expected to become epidemic. ScienceDaily. Retrieved March 31, 2015 from www.sciencedaily.com/releases/2010/02/100224103353.htm

Wiley-Blackwell. "Dementia in extreme elderly population expected to become epidemic." ScienceDaily. www.sciencedaily.com/releases/2010/02/100224103353.htm (accessed March 31, 2015).

Featured Research

Mar. 31, 2015  Researchers have illuminated an important distinction between mice and humans: how human livers heal. The difference centers on a protein called PPAR alpha which activates liver ... full story

Mar. 31, 2015  Researchers have recorded the first direct observations of the micro-scale mechanisms behind the ability of skin to resist tearing. The results could be applied to the improvement of artificial skin, ... full story

Mar. 31, 2015  Fewer than half of the physicians trained in the United States in 2013 received formal education or training on the subject of exercise, according to new research. "There are immense medical benefits ... full story

Mar. 31, 2015  Memory and as well as connections between brain cells were restored in mice with a model of Alzheimer's given an experimental cancer drug, researchers report. "With this treatment, cells under ... full story

Mar. 31, 2015  Increasing state alcohol taxes could prevent thousands of deaths a year from car crashes, say researchers, who found alcohol-related motor vehicle crashes decreased after taxes on beer, wine and ... full story

Mar. 31, 2015  Alcoholism takes a toll on every aspect of a person's life, including skin problems. Now, a new research report helps explain why this happens and what might be done to address it. "The clinical ... full story

Mar. 31, 2015  A new population of 'memory' immune cells has been discovered by scientists, throwing light on what the body does when it sees a microbe for the second time. This insight, and others like it, will ... full story

Mar. 31, 2015  Coronary heart disease and stroke, two of the leading causes of death in the United States, are diseases associated with heightened platelet reactivity. A new study in humans suggests an underlying ... full story

Mar. 31, 2015  A new study had researchers seeking answers to why the therapeutic benefit afforded by SSRIs was so limited in children and teenagers. If researchers can uncover the biological mechanisms preventing ... full story

Featured Videos

Solitair Device Aims to Takes Guesswork out of Sun Safety

Reuters - Innovations Video Online (Mar. 31, 2015)  The Solitair device aims to take the confusion out of how much sunlight we should expose our skin to. Small enough to be worn as a tie or hair clip, it monitors the user&apos;s sun exposure by taking into account their skin pigment, location and schedule. Matthew Stock reports.
Video provided by Reuters

Soda, Salt and Sugar: The Next Generation of Taxes

Washington Post (Mar. 30, 2015)  Denisa Livingston, a health advocate for the Dinι Community Advocacy Alliance, and the Post&apos;s Abby Phillip discuss efforts around the country to make unhealthy food choices hurt your wallet as much as your waistline.
Video provided by Washington Post

S. Leone in New Anti-Ebola Lockdown

AFP (Mar. 28, 2015)  Sierra Leone imposed a three-day nationwide lockdown Friday for the second time in six months in a bid to prevent a resurgence of the deadly Ebola virus. Duration: 01:17
Video provided by AFP

Related Stories

Aug. 27, 2013  Patients with a diagnosis of dementia have approximately three times the rate of diagnosis of urinary incontinence, and more than four times the rate of fecal incontinence, compared with those ... full story

Aug. 15, 2012  People who are free of dementia and have high levels of a protein that indicates the presence of inflammation have relatives who are more likely to avoid the disease as well, according to a new ... full story

June 11, 2012  Our attitude towards our age has a massive impact on the likelihood of being diagnosed with dementia, new research suggests. New research shows that when seniors see themselves as 'older' ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.